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The Structure and Properties of Carbon Fiber Based Adsorbent Monoliths

Description: Carbon fiber monoliths manufactured by a novel slurry molding process from isotropic pitch-derived fibers are being developed at ORNL for gas separation and storage applications [1]. Low density (p = 0.2 - 0,3 g/cm3) monoliths have been successfully demonstrated to have an acceptable pressure drop for gas separation applications and are currently being developed for C02/CH4 separations, whereas monoliths with densities in the range p = 0.4 - 0.6 g/cm3 have been "shown to have natural gas storage capacities of >100 VIV at 500 psi pressure and room temperature. Thermal conductivity, as a function of temperature, was measured using the LASER flash, thermal- pulse method. Another approach to minimizing the temperature gradients that develop in a storage bed is to increase the thermal conductivity of the adsorbent carbon. To this end, we have developed hybrid monoliths that contain small fractions of mesophase pitch- derived carbon fibers. Our hybrid monoliths exhibit thermal conductivities in the range 0.2-0.9 W/m.K depending on the blend and density of the monolith. In comparison, a packed bed of granular carbon at comparable density would have a thermal conductivity of approximately 0.1 W/m.K [ 1 ]. The thermal conductivities of several of the hybrid The improved thermal conductivity of our monoliths is attributed to the bonding between the fibers and the incorporation of high thermal conductivity, mesophase pitch-derived carbon fibers. These features are visible in the SEM micrograph in Fig. 4.
Date: November 6, 1998
Creator: Burchell, T.; Judkins, R.R.; Rogers, M.R. & Shaw, W.S.
Partner: UNT Libraries Government Documents Department

Adsorption and Ultrasound-Assisted Sorbent Regeneration

Description: This work was conducted for the department of Energy. In this work, we developed a class of new sorbents that were highly sulfur selective and had high sulfur capacities. The study consisted of two sections. Development of the new sorbents is described in Section 1, and Section was a fundamental study, conducted for a better understanding for desulfurization of jet fuels. More details of the results are given blow separately for the two sections.
Date: September 30, 2006
Creator: Wang, Yuhe; Ma, Liping & Yang, Ralph T.
Partner: UNT Libraries Government Documents Department

Investigation of Combined S02/N0x Removal by Ceria Sorbents

Description: Simultaneous removal of S02 and NOX using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual S02 and NOX removal operations. Recent studies at PETC considered cerium oxide as an alternate sorbent to CUO. The present study aims to determine the effects of ammonia on ihe sulfation of the sorbent and to obtain a rate expression for the regeneration of alumina-supported CeOa sorbents. In the past quarter the effect of cerium content of the sorbent on its performance through four sulfation-regeneration cycles were investigated and the analysis of the economics of a commercial scale ceria process wcs sub-contracted to TECOGEN. It was found that all ceria sorbents did not show any capacity loss after the first cycle and, in fact, their performance improved slightly after the third cycle. Increasing cerium loading appears to reduce the S/Cc ratio to about 2 as monolayer coverage is approached. It was found that the sulfation rate for the sorbents containing 9.28% and 7.64% cerium were first order with respect to cerium oxide up to 90% conversion. The sorbents containing 4.39% and 1.59 showed first order kinetics up to only about 40% conversion. The effects of product layer diffusion and gas phase diffusion are currently being considered for these sorbents.
Date: April 1, 1996
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Partner: UNT Libraries Government Documents Department

INVESTIGATION ON DURABILITY AND REACTIVITY OF PROMISING METAL OXIDE SORBENTS DURING SULFIDATION AND REGENERATION

Description: The main objective of this research project during this quarter is to investigate effects of hydrogen on initial absorption as well as equilibrium absorption of 2500-ppm H2S into 0.1-g TU-188 sorbent in the presence of 10 vol % moisture at the 0.12-s space time and 530 o C.
Date: August 1, 1998
Creator: Kwon, K. C.
Partner: UNT Libraries Government Documents Department

INVESTIGATION ON DURABILITY AND REACTIVITY OF PROMISING METAL OXIDE SORBENTS DURING SULFIDATION AND REGENERATION

Description: The main objectives of this research project during this quarter are to investigate effects of hydrogen, moisture, concentrations of H<sub>2</sub> S, and residence time of reaction gas mixtures on equilibrium absorption as well as dynamic absorption of H<sub>2</sub> S into the TU-188 sorbent at 530 o C, and to evaluate effective diffusivity of H<sub>2</sub> S through the sorbent particles, using the newly-fabricated differential reactor.
Date: December 1, 1997
Creator: KWON, K.C.
Partner: UNT Libraries Government Documents Department

Investigation of Combined S02/N0x Removal by Ceria Sorbents

Description: Simultaneous removal of S02 and NOx using a regenerable solid sorbent will constitute an important improvement over the use of separate processes for the removal of these two pollutants from stack gases and possibly eliminate several shortcomings of the individual S02 and NOx removal operations. Recent studies at PHC considered cerium oxide as an alternate adsorbent to CuO. The present study aims to determine the effects of ammonia on the sulfation of the sorbent and to obtain a rate expression for the regeneration of alumina-supported CeOz sorbents. In the past quarter the effect of fly-ash, ammonia, and water on the sulfation of the sorbent was investigated. The analysis of the economics of a commercial scale ceria process has been sub-contracted to TECOGEN. This work has been completed and the report has been received.
Date: July 1, 1996
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Partner: UNT Libraries Government Documents Department

Investigation of combined S02/N0x Removal by Ceria Sorbents

Description: This final report describes the work done under the sponsorship of the U.S. DOE for the support of advanced fossil resource utilization research at historically black colleges and universities, Grant No. DE-Ps22-92MT920 on "Investigation of Combined S02/NOx Removal by Ceria Sorbents". The work was conducted at the Department of Chemical Engineering of Hampton University. The industrial partner was Malcolm Pirnie,Inc. Environmental Engineers, Scientists and Planners, who handled the metal analysis and XRD measurements on the solid sorbents; they have also supplied the flyash used in the experimental program. The development of a commercial process concept, economic analysis, and evaluation of process alternatives were undertaken by TECOGEN of Waltham, MA.
Date: November 1, 1996
Creator: Akyurtlu, Ates & Akyurtlu, Jale F.
Partner: UNT Libraries Government Documents Department

SEQUESTERING AGENTS FOR METAL IMMOBILIZATION APPLICATION TO THE DEVELOPMENT OF ACTIVE CAPS IN FRESH AND SALT WATER SEDIMENTS

Description: This research evaluated the removal of inorganic contaminants by a variety of amendments and mixtures of amendments in fresh and salt water. A series of removal and retention batch experiments was conducted to identify the best treatment for metal removal. Metal removal by the amendments was evaluated by calculating the partition coefficient and percent removal. Retention of metals by the amendments was evaluated in retention (desorption) studies in which residue from the removal studies was extracted with 1 M MgCl{sub 2} solution. The results indicated that phosphate amendments, some organoclays (e.g., OCB-750), and the biopolymer, chitosan, are very effective in removal and retention of metals in both fresh and salt water. These amendments are being evaluated further as components in the development of active caps for sediment remediation.
Date: November 17, 2006
Creator: Knox, A & Michael Paller, M
Partner: UNT Libraries Government Documents Department

Novel Adsorbent-Reactants for Treatment of Ash and Scrubber Pond Effluents

Description: The overall goal of this project was to evaluate the ability of novel adsorbent/reactants to remove specific toxic target chemicals from ash and scrubber pond effluents while producing stable residuals for ultimate disposal. The target chemicals studied were arsenic (As(III) and As(V)), mercury (Hg(II)) and selenium (Se(IV) and Se(VI)). The adsorbent/reactants that were evaluated are iron sulfide (FeS) and pyrite (FeS{sub 2}). Procedures for measuring concentrations of target compounds and characterizing the surfaces of adsorbent-reactants were developed. Effects of contact time, pH (7, 8, 9, 10) and sulfate concentration (0, 1, 10 mM) on removal of all target compounds on both adsorbent-reactants were determined. Stability tests were conducted to evaluate the extent to which target compounds were released from the adsorbent-reactants when pH changed. Surface characterization was conducted with x-ray photoelectron spectroscopy (XPS) to identify reactions occurring on the surface between the target compounds and surface iron and sulfur. Results indicated that target compounds could be removed by FeS{sub 2} and FeS and that removal was affected by time, pH and surface reactions. Stability of residuals was generally good and appeared to be affected by the extent of surface reactions. Synthesized pyrite and mackinawite appear to have the required characteristics for removing the target compounds from wastewaters from ash ponds and scrubber ponds and producing stable residuals.
Date: January 31, 2010
Creator: Batchelor, Bill; Han, Dong Suk & Kim, Eun Jung
Partner: UNT Libraries Government Documents Department

Arsenic and chromium partitioning in a podzolic soil contaminated by chromated copper arsenate

Description: This research combined the use of selective extractions and x-ray spectroscopy to examine the fate of As and Cr in a podzolic soil contaminated by chromated copper arsenate (CCA). Iron was enriched in the upper 30 cm due to a previous one-time treatment of the soil with Fe(II). High oxalate-soluble Al concentrations in the Bs horizon of the soil and micro-XRD data indicated the presence of short-range ordered aluminosilicates (i.e. proto-imogolite allophane, PIA). In the surface layers, Cr, as Cr(III), was partitioned between a mixed Fe(III)/Cr(III) solid phase that formed upon the Fe(II) application (25-50%) and a recalcitrant phase (50-75%) likely consisting of organic material such as residual CCA-treated wood. Deeper in the profile Cr appeared to be largely in the form of extractable (hydr)oxides. Throughout the soil, As was present as As(V). In the surface layers a considerable fraction of As was also associated with a recalcitrant phase, probably CCA-treated woody debris, and the remainder was associated with (hydr)oxide-like solid phases. In the Bs horizon, however, XAS and XRF findings strongly pointed to the presence of PIA acting as an effective adsorbent for As. This research shows for the first time the relevance of PIA for the adsorption of As in natural soils.
Date: June 1, 2008
Creator: Nico, Peter; Hopp, Luisa; Nico, Peter S.; Marcus, Matthew A. & Peiffer, Stefan
Partner: UNT Libraries Government Documents Department

Engineered Natural Geosorbents for In Situ Immobilization of DNAPLs and Heavy Metals

Description: Extensive subsurface contamination by dense non-aqueous phase liquid (DNAPL) organic solvents and heavy metals is common place at many DOE facilities. Poor performances and excessive costs have made traditional technologies and approaches less than satisfactory for remediation of such sites. It is increasingly apparent that marginal improvements in conventional methods and approaches will not suffice for clean up of many contaminated DOE sites. Innovative approaches using new and/or existing technologies in more efficient and cost-effective ways are thus urgently required.
Date: December 1, 2006
Creator: Weber, Walter J.; Fair, Gordon M. & Boyce, Earnest
Partner: UNT Libraries Government Documents Department

Vapor and gas sampling of single-shell tank 241-U-104 using the in situ vapor sampling system

Description: The Vapor Issue.Resolution Program tasked the Vapor Team (VT) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-U-104. This document presents In Situ Vapor Sampling System (ISVS) data resulting from the July 16, 1996 sampling of SST 241-U-104. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory (PNNL) which supplied and analyzed the sample media.
Date: August 5, 1997
Creator: Lockrem, L.L.
Partner: UNT Libraries Government Documents Department

Vapor and gas sampling of single-shell tank 241-C-107 using the vapor sampling system

Description: The Vapor Issue Resolution Program tasked the Vapor Team (the team) to collect representative headspace samples from Hanford Site single-shell tank (SST) 241-C-107. This document presents sampling data resulting from the March 26, 1996 sampling of SST 241-C-107. Analytical results will be presented in separate reports issued by the Pacific Northwest National Laboratory which supplied and analyzed the sample media. The team collected representative headspace samples using the In Situ Vapor Sampling System (ISVS).
Date: August 5, 1997
Creator: Lockrem, L.L.
Partner: UNT Libraries Government Documents Department

SULFUR REDUCTION IN GASOLINE AND DIESEL FUELS BY EXTRACTION/ADSORPTION OF REFRACTORY DIBENZOTHIOPHENES

Description: Refractory 4,6-dimethyldibenzothiophene, which is difficult to remove from petroleum feedstocks, binds to the Ru in Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} by displacing the H{sub 2}O ligand. Thiophene, benzothiophene and dibenzothiophene (DBT) also react with Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} similarly. This binding ability of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+} has been used to remove over 50% of the DBT in simulated petroleum feedstocks by a biphasic extraction process. The extraction phase is readily regenerated by air-oxidation thereby completing a cyclic process that removes DBT from petroleum feedstocks. Solid phase extractants consisting of Ru(NH{sub 3}){sub 5}(H{sub 2}O){sup 2+}, CpRu(CO){sub 2}(BF{sub 4}), CpFe(CO){sub 2}(C{sub 4}H{sub 8}){sup +} and AgX (where X = BF{sub 4}{sup -}, PF{sub 6}{sup -} or NO{sub 3}{sup -}) adsorbed on silica have also been used to remove DBT and 4,6-Me{sub 2}DBT from simulated petroleum feedstocks. The AgX/silica adsorbents remove 90% of the DBT and 4,6-Me{sub 2}DBT and can be regenerated and re-used for multiple extractions, which makes these adsorbents of potential industrial use for the removal of refractory dibenzothiophenes from petroleum feedstocks.
Date: June 1, 2003
Creator: Angelici, Robert J.
Partner: UNT Libraries Government Documents Department

Review of arsenic removal technologies for contaminated groundwaters.

Description: This review was compiled to summarize the technologies currently being investigated to remove arsenic from drinking waters, with a special focus on developing and third-world countries where the problem is exacerbated by flooding and depressed economic conditions. The reason for compiling this report is to provide background material and a description of competing technologies currently described in the literature for arsenic removal. Based on the sophistication and applicability of current technologies, Argonne National Laboratory may develop an improved method based on magnetic particle technology. Magnetic particle sorbents may afford improved reaction rates, facilitate particle-water separation, and offer reusability. Developing countries like Vietnam and Bangladesh cannot afford expensive, large-scale treatments to remove arsenic from drinking waters to acceptable limits (from 50 ppb to 10 ppb, depending on the country). Low-cost, effective technologies that can be readily available at the household or community level are needed to solve the present crisis. Appropriate technologies should meet certain criteria, including the following: The treatment must be applicable over a wide range of arsenic concentrations; It should be easy to use without running water or electricity; and The materials for the treatment should be cheap and readily available, and/or suitable for reuse. Our review of arsenic removal technologies and procedures indicates that iron filings, ferric salts, granular ferric hydroxide, alumina manganese oxide, Aqua-bind., and Kimberlite tailings are potentially low-cost sorbents that can remove arsenic after simple mixing in a relatively short time. However, all these technologies suffer from significant shortcomings. Ferric salts are cheap and very effective at removing arsenic but the reaction rates are slow. Fixed-bed columns make use of activated alumina and iron-coated sands but do not work well with groundwater having high concentrations of iron because iron precipitates in the presence of air, which could clog and foul the column. Synthetic sorbents ...
Date: May 2, 2003
Creator: Vu, K. B.; Kaminski, M. D. & Nunez, L.
Partner: UNT Libraries Government Documents Department

Hot Gas Desulfurization PDU Project

Description: The process development unit (PDU) being constructed at METC will fill the strategic role of bridging the gap between post/current small-scale testing and future large-scale demonstrations. With the capability for both fluid-bed and transport reactor contacting, the project will provide a site for testing/proving hot gas desulfurization (HGD) process configurations and demonstrating sorbent suitability. Process conditions will be representative of anticipated commercial applications in terms of temperatures, pressures, compositions, velocities, and sorbent cycling.
Date: December 31, 1996
Creator: Bissett, L.A.
Partner: UNT Libraries Government Documents Department